This file is an exploratory analysis of the effect of climate-induced shifts in angler catch-per-trip of Gulf of Maine cod and haddock. Results are based on 100 iterations of the recreation demand model. The RDM is calibrated to 2020 fishery conditions.

Baseline (2020) fishery statistics

Index “_i” indicates per choice occasion variable

           variable     mean       sd
    estimated_trips   312755   0.9488
 n_choice_occasions 478266.5 2082.485
      tot_cod_catch   587592 1805.091
       tot_keep_cod  4882.56  51.4635
        tot_rel_cod 582709.4 1802.771
     tot_hadd_catch  1924576 3704.324
      tot_keep_hadd 998495.9 1670.146
       tot_rel_hadd   926080 2253.206
         cod_keep_i   0.0102    1e-04
        hadd_keep_i   2.0878   0.0095
      cod_keep_trip   0.0156    2e-04
     hadd_keep_trip   3.1926   0.0053
        cod_catch_i   1.2286   0.0057
       hadd_catch_i   4.0241   0.0182
     cod_catch_trip   1.8788   0.0058
    hadd_catch_trip   6.1536   0.0118

Baseline welfare calculations

After calibrating the simulation model to 2020 fishery conditions, I re-ran the model under two closure scenarios: (a) bag limits for both cod and haddock set to zero, and (b) bag limits for cod only set to zero.
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Scenario (a): close both fisheries

CV per choice occasion

 mean  sd
 66.1 0.4

Aggregate CV

     mean       sd
 31611510 152193.5

Number of trips under closure

     mean    sd
 256727.6 566.3

Number of trips under baseline fishery

   mean   sd
 312755 0.95

Percent reduction in trips from baseline fishery

   mean   sd
 -17.91 0.18

Scenario (b): close cod only

CV per choice occasion

 mean   sd
 0.89 0.17

Aggregate CV

     mean       sd
 423960.4 79141.42

Number of trips under closure

   mean    sd
 312053 168.4

Number of trips under baseline fishery

   mean   sd
 312755 0.95

Percent reduction in trips from baseline fishery

  mean   sd
 -0.22 0.05

Annual fishery outcomes under climate-induced changes in catch-per-trip

Each tab contains projected fishery outcomes based on input data from alternative copula models.

Clayton (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Clayton (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Gumbel (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Gumbel (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Frank (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Frank (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Plackett (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Plackett (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Gaussian (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Gaussian (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

All copulas (correlated catch, decade=1)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

All copulas (correlated catch, decade=4)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

All copulas (correlated catch, decade=8)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

OLS meta-analaysis of simulation results

The following OLS regression uses as data the 10 sets of results above (5 copulas, each with independent and correlated catch).
OLS results of total monthly CV

OLS results of total monthly CV

Monthly fishery outcomes under climate-induced changes in catch-per-trip

For reference, here are the number of directed trips by mode and period (1st and 2nd half of month) in 2020 used to calibrate the model.

Number of directed trips for cod and haddock in 2020.
mode1 month period dtrip cod_bag cod_min hadd_bag hadd_min
pr 4 7 24807 0 100 15 17
fh 5 9 1102 0 100 15 17
pr 5 9 15297 0 100 15 17
fh 5 10 5487 0 100 15 17
pr 5 10 14406 0 100 15 17
fh 6 11 5354 0 100 15 17
pr 6 11 25195 0 100 15 17
fh 6 12 1760 0 100 15 17
pr 6 12 22111 0 100 15 17
fh 7 13 3702 0 100 15 17
pr 7 13 16609 0 100 15 17
fh 7 14 13604 0 100 15 17
pr 7 14 37126 0 100 15 17
fh 8 15 5241 0 100 15 17
pr 8 15 16028 0 100 15 17
fh 8 16 6608 0 100 15 17
pr 8 16 13384 0 100 15 17
fh 9 17 5420 1 21 15 17
pr 9 17 13822 0 100 15 17
fh 9 18 5448 1 21 15 17
pr 9 18 23918 1 21 15 17
fh 10 19 294 0 100 15 17
pr 10 19 3559 0 100 15 17
fh 10 20 449 0 100 15 17
pr 11 21 32024 0 100 15 17
MRIP point estimates of directed trips in 2020 by bi-monthly period

MRIP point estimates of directed trips in 2020 by bi-monthly period

Each tab below contains projected fishery outcomes at the monthly level based on input data from alternative copula models. ## {.tabset} ### Clayton (independent catch) Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Clayton (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Gumbel (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Gumbel (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Frank (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Frank (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Plackett (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Plackett (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Gaussian (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Gaussian (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

MC simulation #2a - annual fishery outcomes with alternative cod open seasons

The baseline open season for cod in 2020 was Sep. 15-30 for private boat and September 7-October 8 for for-hire. Because the model time-step is bi-monthly (two periods per month: 1st half, 2nd half), I set the private open season to the 2nd half of September and the for-hire season to the 1st and 2nd half of September. Haddock was open all months except March and the first half of April (when there was no directed trips).

I specified alternative cod open seasons by month for May, June, July, August, and October. To do this, I open the 2nd half of the month for private boat mode, and I open the 1st and 2nd half of the month for the for-hire mode.

In these simulations I use independent and correlated catch-per-trip data from the clayton copula model.

Main welfare results below show the difference in total CV between baseline cod open season, and cod open season in an alternative month.

Independent (decade=1)

Independent (decade=5)

Independent (decade=8)

Correlated (decade=1)

Correlated (decade=5)

Correlated (decade=8)

Each tab below contains projected fishery outcomes based on input data from alternative copula models. Here, I opened the cod season in different periods across the year.

Clayton (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Clayton (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

MC simulation #2b - monthly fishery outcomes with alternative cod open seasons

Each tab contains projected fishery outcomes at the monthly level based on input data from alternative copula models. Here, I opened the cod season in different periods across the year.

The baseline open season for cod in 2020 was Sep. 15-30 for private boat and September 7-October 8 for for-hire. Because the model time-step is bi-monthly (two periods per month: 1st half, 2nd half), I set the private open season to the 2nd half of September and the for-hire season to the 1st and 2nd half of September. Haddock was open all months except March and the first half of April (when there was no directed trips).

I specified alternative cod open seasons by month for May, June, July, August, and October. To do this, I open the 2nd half of the month for private boat mode, and I open the 1st and 2nd half of the month for the for-hire mode.

In these simulations I use independent and correlated catch-per-trip data from the clayton copula model.

May open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

June open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

July open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

August open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

September open (baseline results) (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

October open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

May open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

June open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

July open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

August open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

September open (baseline results) (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

October open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):